The present invention relates generally to armor-piercing projectiles and specifically to armor-piercing projectiles having a luminated or layered construction.
The primary function of an armor-piercing projectile is to penetrate the armor surrounding otherwise vulnerable targets, such as intricate machines or personnel. The effectiveness of the projectile depends fundamentally on its kinetic energy, i.e., the higher the mass or velocity, the greater the terminal effects on the target.
The projectile may be defeated upon impacting the hardened target by shock-induced brittle fracture for high hardness projectiles, termed "breakup", or by excessive plastic flow for tough, ductile projectiles, termed "mushrooming". A high penetrating capability using a monolithic projectile typically is difficult to achieve, since generally high hardness and high toughness are to some extent mutually exclusive metallurgical properties. As is known, a compound projectile, consisting of a tough core surrounded by a hardened shell, tends to strike a balance between the properties of hardness needed to penetrate and toughness needed to maintain structural integrity.
This concept has been extended to utilize multilaminations of a selected hardness and toughness gradient such that hardness decreases and toughness increases from the outer layer to the inner core. Thus, a number of layers must be broken up before the structural integrity of the core is jeopardized. Further, the interfaces between the layers apparently serve to interrupt brittle crack propagation and to act as acoustical scattering surfaces tending to diminish resonant excitation. This approach is shown in U.S. Pat. No. 4,044,679 "Laminated Armor-Piercing Projectile", issued Aug. 30, 1977, to V. Pagano and S. Tasdemiroglu. However, the improved penetrating capability of the multilayered design is apparently attained at the expense of increased complexity of manufacture.